mcgrath



(No Model.)

P. O. MOGRATH. BALL GRINDING MACHINE.

Patented 17,1896.

UNITED STATES PATENT OFFICE.

PATRICK C. MCGRATH, OF'RUTLANI), VERMONT, ASSIGNOR OF ONEJIALF TOI-IARTIVELL A. DALRYMILE, OF SAME PLACE.

BALL-GRINDING MACHINE.

SPECIFICATION forming part of Letters Patent No. 556,364, dated March1'7, 1896.

Application filed May 1, 1895. Serial No. 547,786- (No model.)

To all whom it may concern.-

Be it known that I, PATRICK O. MOGRATH, a citizen of the United States,residing at Rutland, in the county of Rutland and State of Vermont, haveinvented a certain new and useful Improvement in Ball-Grindin gMachines, of which the following is a full, clear, and exactdescription.

This invention has for its object the production of a simple andeasily-operated machine for grinding balls for ball-bearings, casters,and other objects, and for grinding or truing spherical bodiesgenerally.

In the machine selected herein in illustration of the principle of myinvention I employ a ball-holder, composed of oppositely rotating disksor plates, in conjunction with subjacent rotary grinders of peculiarc011- struction, and these several main elements of my machine areprovided with appropriate means for adjusting them in position andrelatively to one another to meet the exigencies of the insertion,grinding and removal of the spheres, all as Iwill proceed nowparticularly to describe and finally claim.

In the accompanying drawings, illustrating my invention, in the severalfigures of which like parts are similarly designated, Figure 1 is avertical sectional elevation, Fig. 2 is a side elevation, Fig. 3 is atop plan view, and Fig. 4 is a cross-section, of a modified form ofgrinder.

a is a bed-plate upon which is mounted the goose-neck stands 1), theselatter being connected by a cross-bar or yoke c, which receives theboxes for the various shafts hereinafter described. The middle shaft orspindle cl is stepped in a foot-step or box d containing theantifriction-blocks d and its upper end is borne in a box 61 on the yoke0, above which it is provided with the drivingpulley d e is a collarfixed to the spindle d by screws e or otherwise.

f is a disk having its periphery beveled and also having a hub f bywhich it is mounted upon the spindle d, it being supported upon thecollar 6 with interposed antifriction-washersf This hub has a flange atits lower end,

and the said hub serves as a band-pulley through which the disk may berotated upon thespindle, the band being shown in section, Fig. 1. Thecollar is adjustable upon the spindle to secure the proper position ofthe disk f.

g is a disk mounted upon the spindle above 7 disk f and having theflanged periphery g, the inner face of the rim of which is beveledcomplementally to the beveled periphery of the disk f to form a troughfor the reception of the spheres tobe ground.

The disk 9 has a lug g which engages a spline or feather g on thespindle, so as to cause the disk to turn with said spindle and alsopermit of the movement of the disk up and down upon the spindle and sofrom and toward the disk f.

The disk 9 is provided with two or more set-screws or other adjustingdevices 9 abutting against disk fto raise and lower the said disk, inorder, respectively, to separate the disks so as to discharge the groundballs and to close the disks upon the balls with sufficient closeness toallow the weight of the upper disk to rest on the balls and confine theballs between the disks, and yet permit free dom of rotation of theballs within the trough while being ground.

In order to adapt the machine to a variety of sizes of balls, I may adda plate h on its inner side, having an annular flange h arranged overthe trough to bear upon the balls and hold them down and in such mannerthat should there be any unusual projections on the balls the saidflange will give and thereby relieve the disks of liability to damage.The upper disk is provided with a slot 9 Fig. 3, to provide for theinsertion of the balls between the disks. Good results will be obtainedby driving these disks in opposite directions at a slow rate of speed,say disk f at about the rate of twenty revolutions a minute and disk gat about the rate of twelve revolutions a minute, and the action ofthese oppositelyrevolving disks upon the balls is to turn them over andover upon themselves quite rapidly, thereby to bring all of their partsin contact with the grinders. For convenience I have hereinbeforereferred to these disks and will again hereinafter refer to them as aholder. I have shown herein two forms of grinders. As seen in Figs. 1, 2and 3, the grinders are most economically employed in pairs. Each ofthese grinders comprises a cup-shaped chuck 2', having a hub 11, bywhich it is readily mounted upon the spindle j to turn with saidspindle. The rim 0? of the chuck is provided with longitudinal slits tand with a beveled portion t, which beveled portion is screw-threadedand receives a screw-threaded ring k, having means, such as holes toreceive a wrench or spanner, whereby the said ring may be turned up ordown to compress the slitted rim of the chuck or to allow the same toexpand relatively to the object contained within the chuck. The grindingdevice proper may be an annulus or disk Z or any suitable grindingmaterial or composition, and it is arranged within the chuck'andconfined therein against displacement by the compression of the rim ofthe chuck thereabout by means of the ring k. The edge of the grindingdevice is presented adjacent to the trough in the holder which containsthe balls. In order to provide for the adjustment of the grinding deviceas its surface is worn away by use, I support the said grinding devicewithin the chuck upon set-screws m. The spindle j is stepped in abox non abracket n, projecting from the stand b, and I prefer to employantifriction-disks or other devices a for the foot-step. The spindle isadjustable vertically in order to bring the grinder in proper proximityto the holder by means of a hand-whcel screw 0 tapped in a threaded(brass) block 02 in the bottom of the bracket n and held in adjustment,as by a set-screw p. The upper end of the spindle j is provided with abox q applied to the yoke c, and above this yoke the said spindle isprovided with a band-pulley '1'. By this construction of grinder it isobvious that the grinding device may be very economically used up.

I prefer to rotate the grinding devices in opposite directions to oneanother, or to 1'0- tate both of them in the same direction, but in adirection opposite to that in which the disk 1" or disk g is rotated.

Instead of the grinding device described I may employ that shown in Fig.4:, which consists of a disk or wheel or other shaped device s, ofgrinding material, provided with a metallic hub s, whichmay be mountedupon the spindle in any appropriate manner. The hub 8 may support thegrinding device .9, and such grinding device may be clamped thereto bymeans of a top plate 5 and screws 8 The grinding device may be of stoneor emery or other suitable material.

One of the pairs of grinding devices may be of coarse material and theother of fine material, to be used successively, or both may be of thesamematerial, in accordance with the work to be done. Obviously, if onegrinding device be of coarse material and the other of fine material thesame machine may not only do the rough work, but may also be used forfinishing, thus economizing in the number of machines to be used in ashop.

I have shown and described my invention as having the shafts arrangedvertically; but I do not wish to limit my invention to that arrangement,since it is obvious that for some purposes the shafts may be arrangedother than vertically.

I have described the discharge of the balls from the holder as beingeffected by raising the upper disk by means of the set-screws; but otherobvious expedients may be similarly employed and the balls may beotherwise discharged.

What I claim is- 1. A ball-grinding machine, comprising a holdercomposed of disks mounted upon a spindle common to both and adapted tore ceive the balls to be ground between them and to present them to thegrinding device, one of the disks rotating with the spindle and theother being rotated thereupon and in an op posite direction and the twodisks being rotated at different speeds, substantially as and for thepurpose described.

2. A ball-grinding machine, comprising a holder composed of disksmounted upon a spindle common to both, a flanged plate interposedbetween them,the said disks and flan ged plate being adapted to receivethe balls to be ground between them and to present them to the grindingdevice, one of the disks rotating with the spindle, and the other beingrotated thereupon and in an opposite direction, and the two disks beingrotated at different speeds, substantially as and for the purposedescribed.

3. A ball-grinding machine, comprising a holder composed of disksmounted upon a spindle common to both, set-screws applied to the upperdisk and abutting against the lower disk, a flanged plate arrangedbetween the said disks, the said disks having their outer edgesconstructed to form a trough wherein in connection with the said flangedplate, the balls to be ground are placed, and by which they arepresented to the grinding device, one of the disks rotating with thespindle, and the other being rotated thereupon and in an oppositedirection andthe two disks being rotated at difierent speeds, substantially as and for the purpose described.

at. In a ball-grinding machine, aholdercomposed of two rotary disks, onehaving its pcriphery beveled, and the other having its peripheryflanged, and the inner face of such flange next to the peripheryof thefirst-named disk complementally beveled to form a trough for thereception of the balls to be ground, the said disks being movablerelatively to one another to discharge the ground balls,

and a spindle upon which one of the disks is rotated and with which the.other rotates, combined with set-screws applied to the upper disk andabutting against the lower disk, substantially as and for the purposedescribed.

5. In a ball-grinding machine, the combination of two or moreemery-wheels of the same or different fineness, shafts, and means todrive them independently, upon which shafts the emery-wheels are mountedand by which they are rotated in opposite directions, and a holdercarrying the balls at a line tangent to the circumference of theemery-wheels, and means to rotate the said holder, whereby the ballsthemselves are rotated upon changeable axes and are ground,substantially as described.

6. In a ball-grinding machine, a grinding device mounted upon a spindle,in combination with a stand in which one end of the spindle is boxed soas to be capable of longitudinal movement, a bracket extending from saidstand in which the lower end of the shaft is stepped, a threaded blockapplied to said bracket, a set-screw for holding said block in place andan adj usting-screw connected with said block and operating against thelower 20 end of the spindle in the direction of its length PATRICK O.MoGRATH. VVit-nesses:

M. J. FRANCISCO, D. FRANCISCO.

